Occurrence
A neurinoma can occur in all sections of the peripheral nervous system. Preferred locations are the cerebellar bridge angle (acoustic neurinoma) or the sensitive nerve roots in the spinal cord (spinal neurinomas). Acoustic neurinomas originate from a part of the auditory and vestibular nerve (vestibulocochlear nerve, VIII cranial nerve) and develop at the point where the nerve exits the brainstem.
This nerve section is located in a channel in the base of the skull, the internal acoustic canal, where the envelope of the peripheral nerve with Schwann cells begins. Schwann cells are cells in nerve tissue that form envelope and support cells that encase and electrically insulate the extension of a nerve cell. Spinal neurinomas can develop at any level of the spinal cord, but are most commonly found in the upper and middle cervical medulla and in the upper thoracic medulla, and their longitudinal extension can extend over several segments.
During expansion, there is often an intraspinal, i.e. in the spinal canal, and extraspinal, i.e. outside the spinal canal, which are connected by a narrow bridge (hourglass tumor). Spinal neurinomas also frequently occur multiple times, especially in neurofibromatosis type 2 (see Causes).
Since the neurinoma originates from the envelope cells of a nerve, it can also be localized in the lumbar spine (lumbar spine). The problem is then usually that even if the tumor grows slowly, the adjacent nerve is compressed. The pressure then causes damage to the nerve cells.
The result is back pain radiating into the leg, so-called lumboischialgia. This can easily be confused with symptoms typical of sciatica. Patients often also notice sensitivity disorders in the leg area.
If the tumor continues to grow, the muscle supplied by the nerve may also weaken. The diagnosis can be made by means of MRI of the lumbar spine. Already in the X-ray image of the spinal column, it is often seen that the lateral opening, i.e. the bony window to the spinal canal, is widened by the tumor growth.
Again, if symptoms persist, microsurgical removal of the tumor is recommended. The neurinoma can also occur in the area of the cervical spine (cervical spine).Here, too, the problem is that the tumor grows only slowly, but can compress adjacent nerves. The pressure then causes damage to the nerve cells.
The consequences are pain in the cervical spine with radiation into the arm or sensitivity disorders. If the tumor continues to grow, the muscle supplied by the nerve may also weaken. The diagnosis can be made by means of an MRI of the cervical spine.
Again, if symptoms persist, microsurgical removal of the tumor is recommended. The problem with a neurinoma in the spinal canal is that the space in the spinal canal is limited. The growth of the neurinoma causes the displacement of the spinal cord.
This can damage the nerve fibers running in the spinal canal. The consequences are usually pain radiating into the arms or legs and sensitivity disorders. The diagnosis is made by means of sectional imaging (MRI of the spinal column or CT).
If symptoms occur, the neurinoma should always be removed surgically. Neurinomas can develop in the area of the entire peripheral nervous system. In addition to the frequent growth in the head and neck region, the extensor sides of the extremities or the spinal/brain nerves, the formation of a neurinoma in the foot is therefore also possible in rare cases.
Clinically, this usually involves a coarse, knotty nerve change in the foot. This is typically sensitive to pressure and touch and can sometimes cause massive pain. In addition, patients often report a permanent tingling and numbness in the area supplied by the damaged nerve.
This is due to the fact that the growth of a neurinoma in the area of the nerve sheath can irritate or compress the adjacent nerve. This irritation of the nerve can be intensified by touch or movement. The foot neurinoma should be distinguished from Morton’s neuralgia.
In this case, constant pressure or a foot malposition causes a reactive proliferation of tissue in the area of the nerve. As a result, the adjacent nerve can also be compressed and damaged. Since the neurinoma can in principle occur on all nerve fibers of the body, a neurinoma can also be localized on the finger or in the hand.
The problem here is that even if the tumor grows slowly, the adjacent nerve is compressed. Symptoms of neurinomas on the finger or hand are usually a painful tingling or numbness in the area supplied by the damaged nerve. This can be determined by a simple clinical test.
Tapping the nerve causes the discomfort described above. This is called a positive Hoffmann-Tinel sign, which also occurs in carpal tunnel syndrome. Here, too, an MRI of the hand must be performed to confirm the diagnosis.
The tumor should then be removed by a hand or neurosurgeon. During microsurgery, the tumor is carefully peeled off the affected nerve. The postoperative results are often very good.
The acoustic neuroma is a benign brain tumor. It develops from the envelope cells of the 8th cranial nerve. This is the auditory and balance nerve.
Acoustic neuroma is one of the most common tumors in the skull. Mostly they occur on one side only. If the tumor exists on both sides, one should think of a neurofibromatosis type 2.
Patients with acoustic neuroma typically suffer from the following symptoms: hearing loss, balance disorders with dizziness, and tinnitus. The diagnosis can be made by MRI or CT. A special hearing test (BERA) to measure the hearing ability at the brain stem is also useful. The therapy of choice should always be surgical removal.
If surgery is performed early, the function of the nerve can be preserved as far as possible. Another therapy option is radiotherapy. This is chosen if the tumor is not operable or the patient’s age or general condition does not allow surgery. If the tumor is completely removed, the prognosis is very good. Life expectancy is not limited.
